What if cameras were rated by true ISO and lenses by t-stop?

Discussion in 'Digital Cameras' started by RichA, Apr 17, 2012.

  1. RichA

    RichA Guest

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  2. RichA

    Alan Browne Guest

    The t-stop of almost all SLR lenses is not worst than the geometric
    aperture - at least not enough to matter. A very few SLR lenses have a
    t-stop that is worse, and in the case of apodization filtered lenses,
    variable t-stops.

    It would be nice if the "natural" (unity gain) ISO of the camera were
    declared. eg: on my camera which begins at ISO 100, the unity gain ISO
    appears to be somewhere around 150 (looking at noise graphs; various
    sources).
     
    Alan Browne, Apr 17, 2012
    #2
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  3. RichA

    Me Guest

    It matters enough for video production - particularly when different
    lenses will be used in multi-camera scenes. If there's a visible
    exposure difference between cameras/lenses, an extra layer of complexity
    is added to the editing process. For still photos, it would make no
    difference to the intended output, or is trivial to adjust in PP.
     
    Me, Apr 18, 2012
    #3
  4. RichA

    Rich Guest

    I've seen incidents where claimed apertures between two lenses produced
    different results. but mostly with older versus newer lenses.
     
    Rich, Apr 18, 2012
    #4
  5. RichA

    Rich Guest

    That would be a good place to set it. But like audio equipment in the
    1970's the camera mfgs will have to be "encouraged" to adhere to a
    standard.
     
    Rich, Apr 18, 2012
    #5
  6. RichA

    Alan Browne Guest

    The amount is small is SLR lenses (say 1/2 stop). In cine lenses, the
    difference between aperture and t-stop can be several stops. What
    you're describing and the differences if SLR claimed aperture, actual,
    light loss, and variance are different issues and much smaller.
     
    Alan Browne, Apr 20, 2012
    #6
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